1. Field of the Invention
The invention relates to vehicles that can be loaded and unloaded using a towmotor, and specifically to wheel chocks used to prevent movement of the vehicle during the loading and unloading operations. More particularly, the invention is directed to a wheel chock apparatus capable of detecting the presence of a tire and indicating to an individual performing a loading or unloading operation whether the trailer is properly chocked.
2. Background Art
Heavy-duty vehicles such as semi-trailers or tractor-trailers typically include a trailer, which can be one of various types that are well-known in the heavy-duty vehicle art, and include van trailers and flatbed trailers. The trailers are used to haul cargo that typically is loaded onto and unloaded from the trailer at a loading dock or docking bay. Such heavy-duty vehicles also include box trucks, which do not have a separate trailer, but nonetheless have a large cargo compartment similar to a van trailer. The loading and unloading operations typically are carried out by an individual operating a forklift or towmotor which is able to lift pallets of cargo and load them onto or unload them from the trailer or cargo compartment. Hereinafter, and unless otherwise specified, when the term “trailer” is used, it will be understood that for ease of description the term also will include the cargo compartments of box trucks.
When a heavy towmotor drives onto a trailer floor or bed and, despite the fact that the vehicle parking or emergency brake may be engaged, a phenomenon called “trailer walk” or other trailer movement can occur. Many heavy-duty vehicles have trailing arm air-ride axle/suspension systems which depend from the vehicle frame and suspend wheels and tires from the trailer to provide a smooth ride to any cargo being carried by the trailer, as well as to occupants of the tractor or vehicle cab. However, the geometry of such air-ride axle/suspension systems can cause the trailer wheels and tires to rotate in a forward direction or away from the loading dock during a loading or unloading operation. This well-known phenomenon thus can create an undesirable and potentially dangerous gap between the rearwardmost edge of a trailer floor and the edge of a loading dock. Other movement of the trailer away from the loading dock, besides classic trailer walk, also can occur. More specifically, on vehicles having trailing or leading arm air-ride or leaf spring axle/suspension systems, and depending on the speed, direction, etc., at which a towmotor enters or exits the trailer, the force of the turning towmotor wheels themselves actually can also force a trailer away from a loading dock, thereby creating an undesirable gap between the trailer floor and docking bay edge.
Thus, as a towmotor repeatedly drives onto and off of a trailer bed to unload or load a trailer, the trailer can have a tendency to “walk” or otherwise move away from the loading dock. Eventually, such walk or other movement can cause the towmotor tires to become stuck between or even fall into the gap created between the trailer bed and the loading dock, which can damage the cargo being loaded/unloaded and/or the towmotor, and possibly even cause injury to the towmotor operator.
As a result of the trailer walk phenomenon and other potential trailer movement, it has been standard practice for many years at loading docks for the driver of a heavy-duty vehicle to chock one or more of the wheels, and typically the two rearwardmost wheels of the trailer, to prevent trailer walk or other movement. Specifically, the chocks typically are wedged in front of the rear tires to block forward motion of the trailer.
However, a towmotor operator typically cannot quickly visually verify that the wheel chocks are correctly wedged against the tires and the surface on which those tires rest, but instead must rely on and trust that the driver has satisfactorily accomplished this task. Unfortunately, a driver occasionally either will forget to position the wheel chocks altogether or position them improperly, so that unbeknownst to the towmotor operator, trailer walk or other trailer movement is occurring, creating a potentially inconvenient or unsafe situation for property and person.
Thus, a long-felt need has existed for an apparatus and/or process of ensuring proper positioning of wheel chocks, and also of indicating to a towmotor operator that the wheel chocks are correctly positioned.
The present invention solves the above-described problems of an unused or improperly positioned wheel chock, by modifying a usual wheel chock with a tire-sensing device that not only detects the proximity of the tire to the chock, thus ensuring that the wheel chock is correctly positioned against the tire, but also indicates to a towmotor operator that the chocks are correctly positioned.